THE THERMAL power sector contributes 87 per cent of total mercury emissions in the country. Mercury emitted by power plants enters water bodies through ash as well as through precipitation from the atmosphere and can enter the human body if contaminated fish is consumed. CSE's Pollution Monitoring Laboratory (PML) conducted a study in 2012 to investigate mercury pollution in Singrauli-Sonbhadra region where several coalbased power plants and coal mines are located. The study revealed alarming levels of mercury in drinking water, fish and human blood and tissue—evidence of mercury poisoning in local population was widespread.
During 2013-14, CSE's PML collected and analysed coal and ash samples from coal mines and thermal power plants from across the country. The study found, on an average, very high (0.61 mg/kg) mercury in domestic coal. India's coal-based power plants are estimated to be emitting around 440 g/GWh of mercury into air and water. India has no regulations to control mercury. But it may now be under pressure to introduce norms as India became a signatory to the Minamata Convention, a UN agreement, in September 2014. China recently stipulated mercury emission norms of 104 g/ GWh. Indian plants will need to cut mercury emission by 75 per cent to meet the Chinese standards. However, the real challenge is to effectively enforce them. CSE estimates total mercury emission may grow to nearly 700 tonnes per annum by 2021-22, if left unchecked.